Which one of the following is NOT a (vas) deferens, epididymis, component of semen?

Correct Answer: A

Rationale: The correct answer is A: sperm. Sperm is not a component of semen; it is the male reproductive cell. Semen is composed of fluids from the epididymis, seminal glands, and prostate, which provide nourishment, protection, and transportation for sperm. The epididymis stores and matures sperm, seminal glands produce seminal fluid, and the prostate contributes prostatic fluid. Sperm is only a part of semen and not a component of it. Therefore, choice A is the correct answer.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Testosterone inhibits the release of luteinizing hormone (LH) through negative feedback. 2. LH is produced by the anterior pituitary. 3. Therefore, testosterone exerts negative feedback on the anterior pituitary to turn off LH secretion. 4. This maintains hormonal balance in the body. Summary of other choices: A. Incorrect because testosterone primarily affects LH secretion, not follicle stimulating hormone (FSH). B. Incorrect as it inaccurately suggests that testosterone turns off both LH and FSH secretion. C. Incorrect because Sertoli cells are involved in spermatogenesis, not LH regulation.

Correct Answer: C

Rationale: The correct answer is C: 400,000,000. During ejaculation, a healthy male typically releases around 200-500 million sperm cells. Choice A (4,000) and B (40,000) are too low compared to the average sperm count. Choice D (4,000,000) is also significantly lower than the typical sperm count, making it incorrect. Therefore, C is the correct answer as it aligns with the standard range of sperm count during ejaculation.

Correct Answer: B

Rationale: The correct answer is B: Cervix. The cervix is the narrow passage that connects the uterus to the vagina. It acts as a barrier between the uterus and the outside environment. The other choices are incorrect because: A: Vagina is the birth canal and does not directly connect the ovary to the uterus. C: Fallopian tube connects the ovary to the uterus but does not directly attach to it. D: Perineorrhaphy is a surgical procedure to repair the perineum and is not related to connecting the ovary to the uterus.

Correct Answer: C

Rationale: The correct answer is C: labia. The labia minora are two inner folds that cover and protect the vaginal opening. This is because the labia minora are part of the external female genitalia and specifically designed to provide protection to the vaginal opening. A: Uterus - Incorrect. The uterus is a separate organ and is not involved in covering or protecting the vaginal opening. B: Fallopian tubes - Incorrect. The fallopian tubes are part of the reproductive system but are not located near the vaginal opening or involved in its protection. D: Vagina - Incorrect. While the vagina is connected to the vaginal opening, it is not the structure that directly covers and protects it.